The package xxl.core.math.functions contains necessary classes and interfaces to work with real-valued functions. Besides a general modelling of a real-valued function also the derivative and the primitive are emulated. In order to be interchangeable several wrapper for real-valued functions are available.
Picking up the idea of online aggregation, classes are provided that compute {@link xxl.core.math.functions.AdaptiveAggregationFunction running aggregates} of an arbitrary figure based on user-defined functions. This also includes {@link xxl.core.math.functions.SplineCompressedFunctionAggregateFunction spline compressed aggregate functions} that only consume a fixed amount of memory.